This is where the confusion lies!
The passport requirements are being applied at different dates for different types of travel. There are 3 different classifications for traveling into the US.
1: Air Travel – (By airplane):
As of January 23, 2007, all travelers – including US and Canadian citizens are now required to have a passport when entering the US by airplane.
2: Sea Travel – (By boat or cruise ship):
The exact deadline for when passports (or similar documentation) will be required for entering the US by sea has not been set. However, current legislation has been passed that requires the deadline to be no later than June 2009. The sea travel deadline will be the same as the land travel deadline.
3: Land Border Travel – (Driving a vehicle or walking across the border):
The exact deadline for when passports (or similar documentation) will be required for entering the US by land has not been set. However, current legislation has been passed that requires the deadline to be no later than June 2009. The land travel deadline will be the same as the sea travel deadline.
Why has the Passport Requirement for Land Border Travel Been Delayed?
Originally, the passport requirements for land border travel were supposed to be implemented by January 2008, but in October 2006, the President signed into law a delay of this deadline until June 2009. The main reason for the delay is because the Department of Homeland Security is attempting to develop a PASS CARD system. This system will create drivers license-sized cards that will serve as limited use passports for land border entries from Mexico and the US. The Senate recognized that the PASS CARD system could not be properly implemented by the original deadline, so they passed the Leahy-Stevens Amendment which delayed the deadline until sometime prior to (or on) June 2009.